fix(stdio): add stdin close/end listeners to prevent zombie/orphan processes

src/FastMCP.ts

@@ -2620,6 +2620,15 @@ export class FastMCP<
 
       await session.connect(transport);
 
+      // Belt-and-suspenders: detect when the MCP client closes its end of
+      // the stdin pipe and shut down the transport so the process doesn't
+      // linger as a zombie/orphan. The upstream SDK fix (PR #2003) handles
+      // this inside StdioServerTransport itself, but adding the listener here
+      // means older SDK versions are also protected.
+      const onStdinClose = () => { transport.close().catch(() => {}); };
+      process.stdin.on("close", onStdinClose);
+      process.stdin.on("end", onStdinClose);
+
       this.#sessions.push(session);
 
       session.once("error", () => {